Shock absorber



2l SHEETS-SHEET 1 W. H- SMITH SHOCK ABSORBER Inventor WLLIAM H. SMITH Attorney Fiel.

Fre. s.

Dec. 18, 1951 Filed April 9. 194'? Dc. la.,` 1951 Filed April 9. 1947 W. H. SMITH SHOCK ABSORBER 2 Simms- Smm 2 Inventor Wil-L-A M H. SM l1 H By g llorney Patented Dec. 18, 1951 snoek ABsoRBER -Willam Herbert Smith;y East. Molesey, England f ApplicationApril 9,. 1.947,- Serial No. 740,497

In Great Britain November 13, 1944 commis.

This invention relates to shockabsorbers and is directed towards the provision of improved means of the kind in which shock is absorbed by energy expended on impact. in movement towads each other of the partswhichhave to. absorb the energy of impact. v

In the shock absorber of the present invention the strain energy involvedin the-bending beyond the elastic limit of a ductile: metal, such as mild` steeL-provides the resistance in movement towards each other of thepartssubjected to shock.

One applicationof the. inventionis to-'the provision of crash. gear for. landing. goods from aircraft and one form of such application willl now be described. y

In the accompanying drawings which illustrate various embodiments of. the. invention:

Fig. 1 shows partlyin section one arrangement in elevation,

Fig. 2 shows a corresponding Yside view,

Fig. 3 shows an alternativev arrangement in perspective before the stripsare in position, 4

Fig. 4 is a correspondingrsectional View with strips in position and the plunger starting to descend,

Fig. 5 shows the shape of the strips after the plunger has reached its lowest position,

Fig. 6 shows an arrangement in which a horizontal strip absorbs energy of impact by reverse bending.

Figs. 7 and 8 show in elevation and plan respectively an arrangement similar to thai-l of Fig. 6 but using a linkage to transmit impulsive forces.

Referring first to Figs. 1 and 2 a mild steel strip I, 3 inches wide and 1,/8 inch thick, passes down the outer sides of Vertical supports 2, over supplementary and main rollers 3, 4 at the tops of the supports, and under the plunger 5.

The gap between the plunger 5 and the vertical supports 2 is sufcient to allow the strips I to pass down between them; in doing so the strips are subjected to a reversing bending action as they pass rst over the supplementary rollers 3 and then over the main rollers 4. The main rollers 4 bear on bushes III running on spindles 30. The supplementary rollers 3 turn on spindles I2.

If the strips are oi constant width the resistance will be constant throughout the deformation stroke; but by making the width variable the resistance may vary with the deformation; it is considered generally preferable to make the resistance somewhat less at the beginning of the stroke than at the end.

In the embodiment of Figs. 3-5 a squarecentral (Cl. 18S- 1) strut 6 passes in to a socket 'I- and two sheet metal strips 8, 9 are so arranged that the plungerL 6 cannot pass into the socket 'l without bending them.

rI'he ductile strips 8, 9 are held in position bya band I3, secured to the socket 'I and oisetto guide the strips. l

The strips 3, 9 are bent on impact over the curved upper surfaces I4 of the socket 'I and the strain energy of this bending operation absorbs thev energy of impact, the'strips 8, iliinally taking the shapes shown in Fig. 5. In the arrangement shown inv Fig. 6 a horizontal ductile metal strip I9 passes over main rollers 201 and supplementary rollers 2 I. The plu-ngerZZ is arranged centrally between the rollers 2li and asV it descends it drives the strip I9 downwardsl and the strain energy necessary to bend it over the rollers 2l) absorbs the energy of impact.

A similar arrangement is shown in Figs; 7- and 8- but in this case the rollers 20, 2|V are carried on links 24, 25 which are pivoted at the top'to an abutment piece 26 and are shaped at the so that they can slide on a surfaceV 28.

Impact causes the plunger 23 to strike the abutment piece 26 and the links 24, 25 then move outwards as the strip I9 is dragged through the rollers.

A sleeve 21 prevents the lower surfaces of the Y strip I9 from sagging.

I claim:

l. A shock absorber in which the energy of impact of two parts moving towards each other is absorbed by the strain energy due to bending a strip of ductile metal beyond its elastic limit, comprising one part comprising a, pair of spaced supports having substantially cylindrically curved surfaces and a mild steel strip extending between said supports and being bent around and extending beyond said curved surfaces, and another part consisting of means movable upon impact to engage said one part and move said strip around said curved surfaces to stress the steel of the strip beyond its elastic limit and absorb the energy of impact by strain energy.

2. A shock absorber in which the energy of imp-act of two parts moving towards each other is absorbed by the strain energy due to bending a strip of ductile metal beyond its elastic limit, comprising a pair of spaced supports having substantially cylindrically curved surfaces, a mild steel strip extending between said supports and being bent around and extending beyond said curved surfaces, and impact means operable upon an impact to engage said strip between said bottom ports and being bent around and extending..

beyond said curved surfaces, and impact means operable upon an impact to move said supports 'l apart to cause relative movement of said strip around said curved surfaces to stress the steel of the strip beyond its elastic limit and absorb the energy of the impact by strain energy.

4. A shock absorber in which the energy of impact of two parts moving towards each other is absorbed by the strain energy due to bending a strip of ductile metal beyond its elastic limit, comprising a plunger having two oppositely disposed parallel sides, two supports havingfs'ubstantial cylindrically curved surfaces with 'their axes in parallel relation to each other and to said parallel plunger sides, said supports being spaced with the curved surfaces spaced to accommodate passage of the plunger therebetween, and an elongated strip of mild steel carried by the supports and bent around said'curved surfaces with the intermediate portion of said strip disposed across the path of movement of the plunger to be driven by the plunger over said curved surfaces to stress the steel of the strip beyond its elastic limit and absorb the energy of the impact by strain energy.

-l 5. A shock absorber in which the energyY of impact of two parts moving towards each other is absorbed by the strain energy due to bending a strip of ductile metal beyond its elastic limit, comprising a plunger having two oppositely disposed parallel sides, two supports which are spaced to accommodate passage of said plunger therebetween, rollers journalled on each support with their axes parallel with each other and with said parallel plunger sides, and a strip of mild steel carried by said supportsand passing under said plunger and around said rollers. whereby movement of said plunger due to impact between said parts moves said strip around said rollers and stresses the steel of the strip beyond its elastic limit and absorbs the energy of the impact by strain energy.

6.'y .Af shock absorber in which the energy of impactof two parts movingtowards each other is absorbed by the strain energy due to bending a `strip of ductile metal beyond its elastic limit,

comprising a plunger of rectangular cross-section, a support dening a rectangular passage for said plunger, rectangularly disposed curved surfaces on said support, and two strips of mild steel disposed at right angles to each other and carried by said support across the passage and around said curved surfaces to strain the steel of the strips beyond its elastic limit and absorb the energy of impact by strain energy.

WILLIAM HERBERT SMITH.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES P ATENTS Number Name Date 689,280 Brown Dec. 17, 1901 689,609 Einfeldt Dec. 24, 1901 778,743 Ewers Dec. 27, .1904

1,198,926 Kemp Sept. 19, 1916 1,530,000 Kauffman Mar. 17, 1925 1,649,841 May Nov. 22, 1927 2,112,673 Lewis Mar. 29, 1938 2,145,125 Moore Jan. 24, 1939 2,275,573 Sturm et al. Mar. 10, 1942 FOREIGN PATENTS Number Country Date 7,161 Switzerland Aug. 4, 1893 18,213 Great Britain Aug. 1l, 1911 18,131 Great Britain 1912 473,941 Germany Mar. 25, 1929l 

